【作者】 蔡建军；

【导师】 孔令斌；

【作者基本信息】 兰州理工大学 ， 材料加工工程， 2010， 硕士

【摘要】 论文综述了超级电容器的国内外现状及超级电容器电极材料的最新研究进展,并且制备了超级电容器电极材料。由于有序介孔碳材料具有规则的排列、比较大的比表面积等优点,本文将有序介孔碳(CMK-3)与聚苯胺复合而制备得到CMK-3/PANI复合电极材料,并且以介孔碳为超级电容器的电极材料组装了混合电容器。研究其作为超级电容器电极材料的电化学性质,具体开展的研究内容如下：1.以SBA-15为模板制备了有序介孔碳材料,并且采用硝酸溶液对CMK-3的表面进行改性和修饰。系统研究了未改性CMK-3(p-CMK-3)及改性CMK-3(m-CMK-3)的结构、形貌特征、孔径大小及孔径分布。并对介孔碳的电化学性能进行了测试分析,结果表明,制备的CMK-3具有二维六方有序结构,结构完整均一且具有较高的有序度,孔径分布主要分布在2～8nm左右,比表面积和孔容大小分别为1206m2／g和1.38cm3／g。CMK-3具有最好的双电层电容性能,可达145F／g。CMK-3在HN03溶液中进行表面修饰,其电容性能有了明显地提高,达到200 F/g。2.将改性后的CMK-3(m-CMK-3)作为载体,通过化学氧化的方法加入PANI中,制得了m-CMK-3/PANI复合材料。并用SEM、循环伏安法、恒流充放电法和交流阻抗法研究了复合电极材料的结构和电化学性质。研究结果表明,PANI颗粒在载体m-CMK-3的碳纤维束上包覆,该复合物结构疏松,呈三维多孔结构,使得孔隙率增加,渗透性改善,有利于促使电解液中的活性离子扩散到电极表面和体相当中,发生氧化还原反应,产生大的法拉第赝电容。m-CMK-3的含量为30 wt%时,m-CMK-3/PANI复合材料比容量高达489 F/g。m-CMK-3的独特的孔结构、大比表面积和表面活性在m-CMK-3/PANI复合材料的结构上起了重要作用,使活性物质PANI更分散,提高了PANI的利用率和循环稳定性。3.为了进一步提高：m-CMK-3/PANI复合材料在超级电容器应用中的功率特性和能量密度,改善m-CMK-3/PANI复合材料循环稳定性。将该复合材料为正极材料,配以介孔碳CMK-3为负极和1mol/L H2SO4和1mol/L NaNO3电解液,组装成为电化学混合电容器,混合电容器的工作电压都提高至1.4V,1mol/L H2SO4中电容量为87.4F/g。经过电化学测试,在5mA/cm2电流密度和1.4V充放电电位条件下,电容器功率密度为206W/kg,能量密度达23.8Wh/kg。在1mol/L NaNO3中,混合电容器的能量密度在大功率情况下衰减小,经过1000次循环容量衰减约10%,充放电效率维持在96%左右,表现出良好的超级电容特性。更多还原

【Abstract】 In this thesis,the newest development in research of supercapacitors and the electrode materials of supercapacitor devices have been reviewed.Because ordered mesoporous carbon CMK-3 exhibit high specific area and highly ordered pore structure, three kinds of nanostructured composites were prepared by using CMK-3 as the supporter and an attempt was made to apply the mass active electrode materials for electrochemical capacitors.The main studies are as follows:1.The ordered mesoporous carbon CMK-3 was synthesized by using SBA-15 as surfactant-template.Chemically modified CMK-3 is prepared by wet-oxidative method in HNO3 solution. Structures, morphologies,pore size distributions and pore volumes of p-CMK-3 and m-CMK-3 have been systemically explored.The electrochemical capacitance characteristic of CMK-3 has also been systemically studied. The result shows that CMK-3 present amorphous structure and highly ordered pore structure with average pore size of among 2～8 nm.The CMK-3 with surface area of about 1206 m2/g and volume of about 1.38 cm3/g yields the best electric layered capacitance, i.e.about 145F/g. After chemically modified CMK-3 in HNO3 solution, the capacitance of CMK-3 has been improved greatly, the specific capacitance is up to 200 F/g.2.By using m-CMK-3 as template, a novel m-CMK-3/PANI composite was successfully prepared by in-situ chemical oxidative polymerization. The microstructure and supercapacitive behaviors of these composites were investigated through SEM, XPS,cyclic voltammetry, charge-discharge and impedance spectroscopy. The particles of PANI on m-CMK-3 with large space between ordered nanowires can be effective to obtain fully reversible and very fast redox behavior, which contribute to the pseudo-capacitance.The maximum SC of m-CMK-3/PANI composite (30 wt% m-CMK-3)was up to 489 F/g. As the support of m-CMK-3,its unique porous structure, large specific surface area and surface activity have played an important role in optimizing the structure of m-CMK-3/PANI composite, making active materials more dispersed as well as improving the availability of PANI and good cycle performance.3.In order to improve the power and energy performances and ameliorate the cycle stability of m-CMK-3/PANI composite electrode for supercapacitors, an electrochemical hybrid capacitor was successfully designed using m-CMK-3/PANI composite and m-CMK-3 as positive and negative electrodes,respectively. The discharge capacity of the hybrid capacitor reached 87.4F/g in a lmol/L H2SO4 electrolyte solution under a current density of 5mA/cm2 and a cell voltage of 1.4 V. The energy density of the hybrid capacitor reached 23.8Wh/kg with a power density of 206 W/kg. When the current density was increased from 5.0 to 50mA/cm2, the capacity of the hybrid capacitor in a 1mol/L NaNO3 electrolyte solution remained at about 80% and it showed excellent high rate charge-discharge performance. Furthermore, the m-CMK-3/PANI hybrid capacitors possessed high charge-discharge efficiency and good cycle performance.更多还原